Internal company or, respectively, private, cooperating communication networks (known in the technical field as corporate networks) are formed by connecting private communication systems that realize telephone and data services, especially telecommunication switching systems. Private communication terminal equipment (telephone and data terminal equipment) can be connected to the communication systems. The connection of the private communication systems (for example, HICOM private branch exchanges of Siemens AG) preferably ensues via a private network on private property and, if not possible via a private network, via dedicated connections of a public communication network (for example, the ISDN or, respectively, Euro-ISDN communication network). Insofar as no private communication network is available, the linking of remote communication systems to a corporate network currently ensues via dedicated connections since a private selection information strategy can usually not be employed given dialed connections via a public switched communication network. This means that remote communication systems with few connected communication terminal equipment, i.e. low traffic flow, can only be linked to a corporate network with high economic outlay (leasing at least one permanent connection of a public communication network).
When the remote communication system represents a customer-associated communication system, for example the remote communication system and the private communication network are assigned to different companies, communication connections directed to the corporate network from the communication terminal equipment connected to the remote communication system are usually set up or, respectively, cleared down via the public communication network according to the signaling thereof and, potentially, a suffix dialing. A utilization of, in particular, the potentially more cost-beneficial private transmission network realized in the corporate network is not possible.